c# - Monitor.Wait() causing elements of the queue to be skipped -

i'm trying pass elements 1 queue next space becomes available. fixedsizequeue example saw here. printing out elements added , removed queue turns out of them skipped. think happens when monitor.wait(queue) called. can me solve this?

class fixedsizequeue<t> : queue<t>             {                 private readonly queue<t> queue = new queue<t>();                 private readonly int maxsize;                 public fixedsizequeue(int maxsize) { this.maxsize = maxsize; }                  public new void enqueue (t item)                 {                     lock (queue)                     {                         while (queue.count >= maxsize)                         {                             monitor.wait(queue);                         }                         queue.enqueue(item);                         if (queue.count == 1)                         {                             // wake blocked dequeue                             monitor.pulseall(queue);                         }                     }                 }                  public new t dequeue()                 {                     lock (queue)                     {                         while (queue.count == 0)                         {                              monitor.wait(queue);                         }                         t item = queue.dequeue();                         if (queue.count == maxsize - 1)                         {                              monitor.pulseall(queue);                         }                         return item;                     }                 }             }      class program         {              static void addcustomertowaitinglist(queue<customer> customers, fixedsizequeue<customer> waitinglist)             {                 customer customer = new customer();                 (int = 0; < 40; i++)                 {                     customer = customers.dequeue();                     waitinglist.enqueue(customer);                 }             }              static void addcustomertoeatinglist(fixedsizequeue<customer> waitinglist, fixedsizequeue<customer> eatinglist)             {                 customer customer = new customer();                 (int = 0; < 40; i++)                 {                     customer = waitinglist.dequeue();                     eatinglist.enqueue(customer);                  }             }              static void removecustomerfromwaitinglist(fixedsizequeue<customer> waitinglist)             {                 customer customer = new customer();                 (int = 0; < 40; i++)                 {                     customer = waitinglist.dequeue();                 }             }              static void removecustomerfromeatinglist(fixedsizequeue<customer> eatinglist)             {                 customer customer = new customer();                 foreach(customer c in eatinglist)                 {                     customer = eatinglist.dequeue();                 }             }              static void main(string[] args)             {                 chef chef = new chef();                 customer customer = new customer();                 queue<customer> customers = new queue<customer>(40);                 fixedsizequeue<customer> eatinglist = new fixedsizequeue<customer>(7);                 fixedsizequeue<customer> waitinglist = new fixedsizequeue<customer>(12);                  thread cafeclock = new thread(new threadstart(cafe.startcounting));                  thread addcustomertowaitinglist = new thread(() => addcustomertowaitinglist(customers, waitinglist));                 thread removecustomerfromwaitinglist = new thread(() => removecustomerfromwaitinglist(waitinglist));                 thread addcustomertoeatinglist = new thread(() => addcustomertoeatinglist(waitinglist,eatinglist));                 thread removecustomerfromeatinglist = new thread(() => removecustomerfromeatinglist(eatinglist));                    (int = 1; <= 40; i++)                 {                     customer.id = i;                     customers.enqueue(customer);                     customer = new customer();                 }                  addcustomertowaitinglist.start();                             removecustomerfromwaitinglist.start();                 addcustomertoeatinglist.start();                 removecustomerfromeatinglist.start();                  console.writeline("end");             }         }